Dyestuff of the indigoid type



Patented Feb. 22, 1938 Samuel Ellingworth, Blackley,

Manchester, England, assignor to Imperial Chemical Industries Limited, a corporation of Great Britain Application September 11,1935;

No Drawing. e I

' Serial No. 40,092

This invention relates to 1 Claim. (01. 260-48) the preparation of new dyestufis of the indigoid type. 'More particularly, the invention comprises the production of new dyestuffs of the following general formula CH; '1 l 7 2 /1iI 6 1 3 3 H c 4 ll FAA? 1' 9 2' 8 I i J wherein the hydrogens in the 4, and 6 positions of the isatin radical may be substituted by halogen or methyl groups and the hydrogens in the 7, 8, 9, 10

and 11 positions of the benzocarbazole radical may be substituted by a methyl v group, and which may be pre pared by condensing above for the methyl-alpha-isatin radicals patent.

benzocarbazole and the orthowill be used in this While the prior art discloses the preparation of dyestufis by condensing 4-hydroxy-1',2'- benzocarbazoles with isatin anilides or halogenisatin anilides (see for instance 241,997, and U. S. Patents and 1,706,902) the compounds of are dark blue or black in shade German Patent 1,108,056, 1,157,485 the series which sufier from the defect of changing quite noticeably on soaping. The compound obtainable according to German Patent 241,997 from the naphthocarbazole and isatin unsubstituted oxyanilide, while it dyes in black shades from a hydrosulfite vat, turns to dark brown on soaping. Those compounds prepared according to U. S. Patent 1,157,485 containing chlorine in the isatin radical which are black on original dying turn to a green on soaping; while distinctly blackishthose containing a methyl group in the carbazole radical, according to U. S. Patent 1,706,902, original vat change to a blue which dye black in the -black on soaping.

I have fonnd that black dyestuffs can be prou d by n e si .l-h d oxy ,2'-na h arbazole, ithan. o hoethy subs i u e s m und wh h ma or ma not b u t e substituted byhalogen or methyl groups in the 5 Hz ring of the isatin or in the benzocarbazole radical, which have superior properties to those heretofore described. These new colors, which are exceedingly fast to light, give deeper shades o black when d or n ed n h av sh 1 nd m e, n tr lra sw cn p i t or dy i light shades thanthe corresponding compounds that contain no methyl group in the 7 (or ortho) position of the isatin radical. e H e The following examples are given to more fully 15 illustrate the preferred method of preparing these new color compounds. Parts used are by Weight.

Example 1 lowing general formula Example 2 23.3 parts of 4-hydroxy-1,2'-benzocarbazole and 25 parts of 7 -methyl-alpha-isatin-o-toluidide are dissolved in 150 parts of toluene. 110 parts of acetic anhydride are added and the temperature held for 10 hours at 40 C. The reaction mass is cooled to 25 and the black crystalline material filtered and washed with toluene. After drying and milling, the paste can be incorporated in a printing gum and when printed on cotton or regenerated cellulose gives neutral gray shades in weak prints and heavy bright black shades in strong prints. The product has the following general formula The 4hydroxy-benzocarbazole maycontain alkyl groups in the '7, 8, 9, 10 or 11 positions, and these compounds may be prepared by any of the known methods (see for instance Journal fiir Praktische Chemie, 1910 (2), vol. 81, page 25); In preparing the methyl substituted carbazole compounds, metaor para-xylidine, ortho-, metaor para-toluidines, etc., may be used as the hydrazine component, condensing these compounds with the alpha-naphthylamine compound which contains a hydroxy or sulfonic acid group in the 5 position. When the naphthylamine sulfonic acid is used, the benzocarbazole sulfonic acid is usually fused with caustic alkalies to produce the corresponding hydroxy-benzooarbazole.

The alpha-isatin-anilide compounds used in this process may be prepared by any of the known methods, such as for instance, the process described by Fierz-David in Dye Chemistry, 1921, pages 161-165. Ortho-toluidine, the 2,3-,

2,4- or 2,5-dimethyl-anilines or the chloro or bromo substitution products of ortho-toluidine or the xylidines containing no substituent in the 6 position may be used in place of aniline in the Sandmeyer reaction.

The condensation of the 4-hydroxy-benzocarbazole compound with the 'T-methyl-alphaisatin compound is effected by heating them together in acetic anhydride with or without the addition of glacial acetic acid or other diluent, 10 the heating being continued until the alphaisatin compound has been consumed. On cooling, the new black dyestuffs crystallize out and may be filtered off.

The dyestuffs of my invention are faster to 15 boiling in soap solutions than any of the known products of this class which do not contain a methyl group in the '7 position of the isatin radical.

The products prepared according to this process may be further halogenated as, for example, by theprocedure outlined in German Patent 241,997, thus giving products having the same desirable properties with slight change in shade.

I claim: 25

The compound of the following formula which dyes cotton in from gray to black shades.

SAMUEL ELLINGWORTH. 

